The translational goal of this Academic and Industrial Partnership research project is to develop a precision oncology protocol using a combination of novel nanotechnology biomarker profiling and intraperitoneal (i. p.) delivery of receptor-targeted theranostic nanoparticles for the effective treatment of cancer patients with massive peritoneal metastasis or peritoneal carcinomatosis (PC). The majority of PC patients not only have unresectable tumors, but also develop ascites accumulation, and are considered incurable. To address this unmet clinical challenge, we propose to develop a novel, targeted therapeutic strategy for treating PC. First, we will develop in vitro assays for the detection of the levels of cell receptor targets and evaluation of therapeutic responses to receptor targeted theranostic nanoparticles in peritoneal tumor cells for selecting PC patients who will benefit the most from the targeted cancer therapy. Results of our preliminary studies have shown that i. p. delivery of urokinase plasminogen activator receptor (uPAR) targeted theranostic magnetic iron oxide nanoparticles (IONPs) had a high efficiency of nanoparticle delivery into orthotopic pancreatic tumors with excellent penetration deep into the tumor center, due to its ability to target tumor cells and tumor stromal endothelial cells, fibroblasts, and macrophages that mediate breakage of the tumor stromal barrier. I. p. delivery of the receptor targeted theranostic IONPs led to a marked reduction of peritoneal tumors and ascites volumes in i. p. metastatic pancreatic and ovarian cancer mouse models. Our project aims to develop a clinically feasible and new precision nanomedicine based treatment that integrates biomarker profiling and treatment response evaluation of tumor cells in peritoneal fluids with i. p. delivery of the biomarker targeted theranostic IONPs carrying a potent drug combination to enhance therapeutic responses in drug resistant i. p. tumors and therefore, improve outcome of the therapy. In Aim 1, an in vitro companion diagnostic kit for the detection of four biomarkers (uPAR, IGF1R, EGFR, and HER2) that are highly expressed in peritoneal tumors will be developed. This system includes EpCAM antibody coated IONPs (30 nm core size) for capturing tumor cells and antibody or peptide ligand conjugated quantum dots (QDs) against the above specified biomarkers. Isolation efficiency and specificity of the biomarker detection will be evaluated in ascites samples obtained from tumor-bearing mice or human PC patients. Sensitivity of enriched tumor cells to receptor targeted theranostic IONPs will be examined. Studies in Aim 2 will develop a dual agent theranostic IONP loaded with doxorubicin (Dox) and conjugated with an uPAR targeting ATF ligand fused with a bacterial toxin (PE38KDEL) and determine the therapeutic efficacy of i. p. delivery in metastatic pancreatic or ovarian tumor xenograft models in nude mice. Simultaneous delivery of a potent toxin and Dox into tumor cells has the potential to overcome chemoresistance. Finally, in Aim 3, preclinical studies on biodistribution, systemic toxicity, dose-response, and pharmacokinetics (PK) /pharmcodynamics (PD) will be conducted in normal and i. p. tumor bearing mice.